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-rw-r--r--lib/msan/msan_linux.cpp262
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diff --git a/lib/msan/msan_linux.cpp b/lib/msan/msan_linux.cpp
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+//===-- msan_linux.cpp ----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of MemorySanitizer.
+//
+// Linux-, NetBSD- and FreeBSD-specific code.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
+
+#include "msan.h"
+#include "msan_report.h"
+#include "msan_thread.h"
+
+#include <elf.h>
+#include <link.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <unwind.h>
+#include <execinfo.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
+
+namespace __msan {
+
+void ReportMapRange(const char *descr, uptr beg, uptr size) {
+ if (size > 0) {
+ uptr end = beg + size - 1;
+ VPrintf(1, "%s : %p - %p\n", descr, beg, end);
+ }
+}
+
+static bool CheckMemoryRangeAvailability(uptr beg, uptr size) {
+ if (size > 0) {
+ uptr end = beg + size - 1;
+ if (!MemoryRangeIsAvailable(beg, end)) {
+ Printf("FATAL: Memory range %p - %p is not available.\n", beg, end);
+ return false;
+ }
+ }
+ return true;
+}
+
+static bool ProtectMemoryRange(uptr beg, uptr size, const char *name) {
+ if (size > 0) {
+ void *addr = MmapFixedNoAccess(beg, size, name);
+ if (beg == 0 && addr) {
+ // Depending on the kernel configuration, we may not be able to protect
+ // the page at address zero.
+ uptr gap = 16 * GetPageSizeCached();
+ beg += gap;
+ size -= gap;
+ addr = MmapFixedNoAccess(beg, size, name);
+ }
+ if ((uptr)addr != beg) {
+ uptr end = beg + size - 1;
+ Printf("FATAL: Cannot protect memory range %p - %p (%s).\n", beg, end,
+ name);
+ return false;
+ }
+ }
+ return true;
+}
+
+static void CheckMemoryLayoutSanity() {
+ uptr prev_end = 0;
+ for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
+ uptr start = kMemoryLayout[i].start;
+ uptr end = kMemoryLayout[i].end;
+ MappingDesc::Type type = kMemoryLayout[i].type;
+ CHECK_LT(start, end);
+ CHECK_EQ(prev_end, start);
+ CHECK(addr_is_type(start, type));
+ CHECK(addr_is_type((start + end) / 2, type));
+ CHECK(addr_is_type(end - 1, type));
+ if (type == MappingDesc::APP) {
+ uptr addr = start;
+ CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+ CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+ CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+
+ addr = (start + end) / 2;
+ CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+ CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+ CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+
+ addr = end - 1;
+ CHECK(MEM_IS_SHADOW(MEM_TO_SHADOW(addr)));
+ CHECK(MEM_IS_ORIGIN(MEM_TO_ORIGIN(addr)));
+ CHECK_EQ(MEM_TO_ORIGIN(addr), SHADOW_TO_ORIGIN(MEM_TO_SHADOW(addr)));
+ }
+ prev_end = end;
+ }
+}
+
+bool InitShadow(bool init_origins) {
+ // Let user know mapping parameters first.
+ VPrintf(1, "__msan_init %p\n", &__msan_init);
+ for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
+ VPrintf(1, "%s: %zx - %zx\n", kMemoryLayout[i].name, kMemoryLayout[i].start,
+ kMemoryLayout[i].end - 1);
+
+ CheckMemoryLayoutSanity();
+
+ if (!MEM_IS_APP(&__msan_init)) {
+ Printf("FATAL: Code %p is out of application range. Non-PIE build?\n",
+ (uptr)&__msan_init);
+ return false;
+ }
+
+ const uptr maxVirtualAddress = GetMaxUserVirtualAddress();
+
+ for (unsigned i = 0; i < kMemoryLayoutSize; ++i) {
+ uptr start = kMemoryLayout[i].start;
+ uptr end = kMemoryLayout[i].end;
+ uptr size = end - start;
+ MappingDesc::Type type = kMemoryLayout[i].type;
+
+ // Check if the segment should be mapped based on platform constraints.
+ if (start >= maxVirtualAddress)
+ continue;
+
+ bool map = type == MappingDesc::SHADOW ||
+ (init_origins && type == MappingDesc::ORIGIN);
+ bool protect = type == MappingDesc::INVALID ||
+ (!init_origins && type == MappingDesc::ORIGIN);
+ CHECK(!(map && protect));
+ if (!map && !protect)
+ CHECK(type == MappingDesc::APP);
+ if (map) {
+ if (!CheckMemoryRangeAvailability(start, size))
+ return false;
+ if (!MmapFixedNoReserve(start, size, kMemoryLayout[i].name))
+ return false;
+ if (common_flags()->use_madv_dontdump)
+ DontDumpShadowMemory(start, size);
+ }
+ if (protect) {
+ if (!CheckMemoryRangeAvailability(start, size))
+ return false;
+ if (!ProtectMemoryRange(start, size, kMemoryLayout[i].name))
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static void MsanAtExit(void) {
+ if (flags()->print_stats && (flags()->atexit || msan_report_count > 0))
+ ReportStats();
+ if (msan_report_count > 0) {
+ ReportAtExitStatistics();
+ if (common_flags()->exitcode)
+ internal__exit(common_flags()->exitcode);
+ }
+}
+
+void InstallAtExitHandler() {
+ atexit(MsanAtExit);
+}
+
+// ---------------------- TSD ---------------- {{{1
+
+#if SANITIZER_NETBSD
+// Thread Static Data cannot be used in early init on NetBSD.
+// Reuse the MSan TSD API for compatibility with existing code
+// with an alternative implementation.
+
+static void (*tsd_destructor)(void *tsd) = nullptr;
+
+struct tsd_key {
+ tsd_key() : key(nullptr) {}
+ ~tsd_key() {
+ CHECK(tsd_destructor);
+ if (key)
+ (*tsd_destructor)(key);
+ }
+ MsanThread *key;
+};
+
+static thread_local struct tsd_key key;
+
+void MsanTSDInit(void (*destructor)(void *tsd)) {
+ CHECK(!tsd_destructor);
+ tsd_destructor = destructor;
+}
+
+MsanThread *GetCurrentThread() {
+ CHECK(tsd_destructor);
+ return key.key;
+}
+
+void SetCurrentThread(MsanThread *tsd) {
+ CHECK(tsd_destructor);
+ CHECK(tsd);
+ CHECK(!key.key);
+ key.key = tsd;
+}
+
+void MsanTSDDtor(void *tsd) {
+ CHECK(tsd_destructor);
+ CHECK_EQ(key.key, tsd);
+ key.key = nullptr;
+ // Make sure that signal handler can not see a stale current thread pointer.
+ atomic_signal_fence(memory_order_seq_cst);
+ MsanThread::TSDDtor(tsd);
+}
+#else
+static pthread_key_t tsd_key;
+static bool tsd_key_inited = false;
+
+void MsanTSDInit(void (*destructor)(void *tsd)) {
+ CHECK(!tsd_key_inited);
+ tsd_key_inited = true;
+ CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
+}
+
+static THREADLOCAL MsanThread* msan_current_thread;
+
+MsanThread *GetCurrentThread() {
+ return msan_current_thread;
+}
+
+void SetCurrentThread(MsanThread *t) {
+ // Make sure we do not reset the current MsanThread.
+ CHECK_EQ(0, msan_current_thread);
+ msan_current_thread = t;
+ // Make sure that MsanTSDDtor gets called at the end.
+ CHECK(tsd_key_inited);
+ pthread_setspecific(tsd_key, (void *)t);
+}
+
+void MsanTSDDtor(void *tsd) {
+ MsanThread *t = (MsanThread*)tsd;
+ if (t->destructor_iterations_ > 1) {
+ t->destructor_iterations_--;
+ CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
+ return;
+ }
+ msan_current_thread = nullptr;
+ // Make sure that signal handler can not see a stale current thread pointer.
+ atomic_signal_fence(memory_order_seq_cst);
+ MsanThread::TSDDtor(tsd);
+}
+#endif
+
+} // namespace __msan
+
+#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD